| Abiotic stress not only has great influence on the growth and development of plants and the quality and yield of crops,but also destroys the stability of the whole ecosystem.Transcription factors can target gene promoter in the specific nucleotide sequence(cis acting element)specific binding protein,as a response to abiotic stress signals and activate or inhibit downstream gene expression of the intermediate links,in response to various abiotic stress plays a very important role.Dehydration responsive element binding protein(DREB)is a kind of important transcription factors,a variety of abiotic stress induced stress induced the expression of genes,in response to drought stress and cold stress,salt stress,high temperature stress process has played a significant role adjustment.Overexpression of DREB transcription factor has also been extensively applied in various plants,however,transgenic test involves many variable factors,and it is difficult to evaluate and analyze the complex physiological mechanism of DREB gene family in plants due to the different gene donors and receptors in different studies and the diversity of drought tolerance evaluation indexes of transgenic plants.Therefore,meta-analysis was applied in this field for comprehensive analysis of DREB overexpression.The meta-analysis of DREB transcription factors in response to stress is helpful to understand the tolerance mechanism and phenotypic changes of plants under abiotic stress.Strawberry(Fragaria vesca)is a kind of perennial herb.With the completion of strawberry genome sequencing,strawberry genome is considered as a new model plant in the rosacea because of its small size(240Mb)and easy genetic transformation.The role of DREB transcription factors in response to abiotic stress has been widely recognized,but there are few studies on this gene family in wild strawberries,and the completion of its sequencing work has laid a foundation for the analysis of the biological function of DREB genes in wild strawberries on the whole genome.We performed a meta-analysis to categorize the response of plant parameters involved in drought tolerance in DREB-overexpressed plants and to evaluate experimental variables that affects transgenic plant performance.The results from across different studies indicated that 8 and 2 of 13 measured parameters exhibited a significant response by increasing or decreasing values by 25%or more in drought-stressed and in non-stressed,control plants,respectively.Among the examined moderating variables,promoters,type of media and stress,donor genus,and recipient genus significantly affected the extent of DREBs’influence.In plants subjected to drought stress,the overexpression of DREB genes derived from Arabidopsis led to greater increases in Fv/Fm(maximum quantum efficiency of photosystem II),relative water content,and proline content.These findings should guide future research on the function of the DREB genes in plant drought tolerance and the use of genetic engineering in drought tolerance breeding.A meta-analysis was conducted of the effect of DREB overexpression on temperature stress tolerance and the various parameters modulated by overexpression that were statistically quantified in 75 published articles.The meta-analysis was conducted to identify the overall influence of DREB on stress-related parameters in transgenic plants,and to determine how different experimental variables affect the impact of DREB overexpression.Viewed across all the examined studies,7 of the 8 measured plant parameters were significantly(p≤0.05)modulated in DREB-transgenic plants when they were subjected to temperature stress,while 2 of the 8 parameters were significantly affected in non-stressed control plants.The measured parameters were modulated by 32%or more by various experimental variables.The modulating variables included,acclimated or non-acclimated,type of promoter,stress time and severity,source of the donor gene,and whether the donor and recipient were the same genus.These variables all had a significant effect on the observed impact of DREB overexpression.Further studies should be conducted under field conditions to better understand the role of DREB transcription factors in enhancing plant tolerance to temperature stress.The expression patterns of 11 FvDREB gene family members under drought stress were analyzed.FvDREB7 in the A-2 subgroup was rapidly up-regulated in the early stage of drought stress,and FvDREB21 and FvDREB1 in the A-4 subgroup and A-1 subgroup were also up-regulated in the later stage of drought stress.The expression level of strawberry drought transcriptome was analyzed,and the response of the members of A-1 and A-2 subgroups to drought stress was up-regulation,and the response of the members of A-4 and A6 subgroups to drought stress was down-regulation.The expression of FvDREB8 in the A-2 subgroup in the new leaves was down-regulated at the initial stress stage.Therefore,different subgroup members of DREB family with strawberry tissue pairs at different developmental stages may play different roles in different stress stages. |
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